Field of the Invention
The present invention relates to a battery terminal applicable to a lithium-ion battery, for example, and a method for manufacturing the terminal battery, and more particularly, it relates to a battery terminal including a first metal layer made of an Al base alloy and a second metal layer made of a Cu base alloy and a method for manufacturing the battery terminal.
Description of the Background Art
A battery terminal including a first terminal member made of an Al base alloy and a second terminal member made of a Cu base alloy is known in general, as disclosed in Japanese Patent Laid-Open No. 2015-060730, for example.
Japanese Patent Laid-Open No. 2015-060730 discloses a connector terminal including a first terminal member and a second terminal member, one of which is made of Cu and the other of which is made of Al, in which the first terminal member and the second terminal member are integrated. The first terminal member of this connector terminal includes a female flange provided with a recessed portion and a shaft portion extending from the female flange toward a first side. The second terminal member includes a male flange fitted into the recessed portion of the female flange and a shaft portion extending from the male flange toward a second side. In the connector terminal according to Japanese Patent Laid-Open No. 2015-060730, the female flange is swaged in a state where the male flange of the second terminal member is fitted into the recessed portion of the female flange of the first terminal member to be in close contact with the female flange of the first terminal member, whereby the first terminal member and the second terminal member are integrated.
Furthermore, in general, on a surface of a battery terminal made of Cu, Ni plating processing is performed in order to facilitate welding such as laser welding when the battery terminal is welded to another member such as a collector of a battery.
In the connector terminal disclosed in Japanese Patent Laid-Open No. 2015-060730, however, even if the first terminal member and the second terminal member are in close contact with each other by swaging, the first terminal member and the second terminal member are simply physically in contact with each other, and hence water, for example, is likely to enter between (interface) the first terminal member and the second terminal member. Thus, electricity flows in between (interface) the first terminal member and the second terminal member through the water, and hence a phenomenon (bimetallic corrosion) in which the terminal member made of metal (Al) easily ionized is corroded (exhausted) is disadvantageously likely to occur. Even if Ni plating processing is performed on a surface of the terminal member of the connector terminal, made of Cu, corrosion is conceivably likely to occur between the first terminal member and the second terminal member that are simply physically in contact with each other, similarly to the case where no Ni plating processing is performed.